1. Field of the Invention
The present Invention relates to computer networks for realtime and non-applications within medical facilities.
2. Description of the Related Art
Many hospitals today are equipped with a hospital information system (HIS) for handling billing, administration, and other business-related matters. Hospitals are also commonly equipped with clinical information systems (CIS) for storing and managing the clinical data of patients. Both types of systems typically operate over a hardwired infrastructure, such as a local area network (LAN).
Hospitals also commonly include special telemetry systems for monitoring the realtime ECG and other physiologic data of patients. Typically, these systems include special wireless transmitters that attach to respective patients, or to the bedside monitors for such patients. Each wireless transmitter transmits the physiologic data of a patient over a wireless channel to a receiving node, which in turn makes the data available for realtime monitoring and viewing on a hardwired monitoring network.
Because of the special requirements associated with handling realtime telemetry data and supporting patient mobility, the hardwired networks used for patient monitoring are normally separate from the networks used for HIS and CIS applications. As a result, the medical facility typically must set up and support two separate computer networks and separate RF networks. Further, existing systems generally do not support wireless access to the HIS, CIS, and other information systems of the hospital LAN.
The present invention seeks to reduce or eliminate these deficiencies while providing new types of wireless applications and services to network users. The invention also provides novel hardware and methods for improving the reliability of wireless LANs.
The present invention provides a wireless local area network (WLAN) system which comprises multiple access points that are distributed throughout a medical facility to provide wireless access to a hardwired network. The access points implement multiple WLAN protocols, including a realtime protocol for realtime patient monitoring (telemetry) and a standard WLAN protocol (such as IEEE 802.11 within an ISM band) for providing general-purpose wireless access. The system thereby allows a single hardwired network to be used for realtime patient monitoring, while providing general-purpose wireless access to resources on the hardwired network such as HIS and CIS databases. Some or all of the access points preferably implement both WLAN protocols such that the different WLANs and wireless device types share network access resources.
In accordance with one aspect of the invention, some or all of the access points may also include RF location-tracking modules that receive signals from patient transceivers and/or other types of location tracking devices. Application software running on the hardwired network uses these devices to rack the locations of patients, hospital personnel, capital equipment, and/or disposable medical supplies. The location data may be stored on the hardwired network by a location-tracking server which makes the data available for near-realtime viewing. The location data may also be used for a variety of other applications, including patient-flow analysis and inventory tracking of disposable equipment.
The present invention also provides an antenna design which may be used with the access points to improve reception (particularly for patient monitoring), and provides a TDMA timeslot rotation method for avoiding lockstep interference between access points that operate on the same channel. In addition, the invention provides various applications for which system may be used, including bedside entry of patient data and prescriptions using wireless writing tablets, the use of wireless barcode scanners to read-in patient ID data from physical charts, and a two-way paging system in which a PDA device may be used to receive alert messages and view corresponding patient data.